/*
 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup lwext4
 * @{
 */
/**
 * @file  ext4_dir_idx.c
 * @brief Directory indexing procedures.
 */

#include <ext4_config.h>
#include <ext4_types.h>
#include <ext4_misc.h>
#include <ext4_errno.h>
#include <ext4_debug.h>

#include <ext4_trans.h>
#include <ext4_dir_idx.h>
#include <ext4_dir.h>
#include <ext4_blockdev.h>
#include <ext4_fs.h>
#include <ext4_super.h>
#include <ext4_inode.h>
#include <ext4_crc32.h>
#include <ext4_hash.h>

#include <string.h>
#include <stdlib.h>

/**@brief Get hash version used in directory index.
 * @param ri Pointer to root info structure of index
 * @return Hash algorithm version
 */
static inline uint8_t
ext4_dir_dx_rinfo_get_hash_version(struct ext4_dir_idx_rinfo *ri)
{
    return ri->hash_version;
}

/**@brief Set hash version, that will be used in directory index.
 * @param ri Pointer to root info structure of index
 * @param v Hash algorithm version
 */
static inline void
ext4_dir_dx_rinfo_set_hash_version(struct ext4_dir_idx_rinfo *ri, uint8_t v)
{
    ri->hash_version = v;
}

/**@brief Get length of root_info structure in bytes.
 * @param ri Pointer to root info structure of index
 * @return Length of the structure
 */
static inline uint8_t
ext4_dir_dx_rinfo_get_info_length(struct ext4_dir_idx_rinfo *ri)
{
    return ri->info_length;
}

/**@brief Set length of root_info structure in bytes.
 * @param ri   Pointer to root info structure of index
 * @param len Length of the structure
 */
static inline void
ext4_dir_dx_root_info_set_info_length(struct ext4_dir_idx_rinfo *ri,
                      uint8_t len)
{
    ri->info_length = len;
}

/**@brief Get number of indirect levels of HTree.
 * @param ri Pointer to root info structure of index
 * @return Height of HTree (actually only 0 or 1)
 */
static inline uint8_t
ext4_dir_dx_rinfo_get_indirect_levels(struct ext4_dir_idx_rinfo *ri)
{
    return ri->indirect_levels;
}

/**@brief Set number of indirect levels of HTree.
 * @param ri Pointer to root info structure of index
 * @param l Height of HTree (actually only 0 or 1)
 */
static inline void
ext4_dir_dx_rinfo_set_indirect_levels(struct ext4_dir_idx_rinfo *ri, uint8_t l)
{
    ri->indirect_levels = l;
}

/**@brief Get maximum number of index node entries.
 * @param climit Pointer to counlimit structure
 * @return Maximum of entries in node
 */
static inline uint16_t
ext4_dir_dx_climit_get_limit(struct ext4_dir_idx_climit *climit)
{
    return to_le16(climit->limit);
}

/**@brief Set maximum number of index node entries.
 * @param climit Pointer to counlimit structure
 * @param limit Maximum of entries in node
 */
static inline void
ext4_dir_dx_climit_set_limit(struct ext4_dir_idx_climit *climit, uint16_t limit)
{
    climit->limit = to_le16(limit);
}

/**@brief Get current number of index node entries.
 * @param climit Pointer to counlimit structure
 * @return Number of entries in node
 */
static inline uint16_t
ext4_dir_dx_climit_get_count(struct ext4_dir_idx_climit *climit)
{
    return to_le16(climit->count);
}

/**@brief Set current number of index node entries.
 * @param climit Pointer to counlimit structure
 * @param count Number of entries in node
 */
static inline void
ext4_dir_dx_climit_set_count(struct ext4_dir_idx_climit *climit, uint16_t count)
{
    climit->count = to_le16(count);
}

/**@brief Get hash value of index entry.
 * @param entry Pointer to index entry
 * @return Hash value
 */
static inline uint32_t
ext4_dir_dx_entry_get_hash(struct ext4_dir_idx_entry *entry)
{
    return to_le32(entry->hash);
}

/**@brief Set hash value of index entry.
 * @param entry Pointer to index entry
 * @param hash  Hash value
 */
static inline void
ext4_dir_dx_entry_set_hash(struct ext4_dir_idx_entry *entry, uint32_t hash)
{
    entry->hash = to_le32(hash);
}

/**@brief Get block address where child node is located.
 * @param entry Pointer to index entry
 * @return Block address of child node
 */
static inline uint32_t
ext4_dir_dx_entry_get_block(struct ext4_dir_idx_entry *entry)
{
    return to_le32(entry->block);
}

/**@brief Set block address where child node is located.
 * @param entry Pointer to index entry
 * @param block Block address of child node
 */
static inline void
ext4_dir_dx_entry_set_block(struct ext4_dir_idx_entry *entry, uint32_t block)
{
    entry->block = to_le32(block);
}

/**@brief Sort entry item.*/
struct ext4_dx_sort_entry {
    uint32_t hash;
    uint32_t rec_len;
    void *dentry;
};

static int ext4_dir_dx_hash_string(struct ext4_hash_info *hinfo, int len,
                   const char *name)
{
    return ext2_htree_hash(name, len, hinfo->seed, hinfo->hash_version,
                   &hinfo->hash, &hinfo->minor_hash);
}

#if CONFIG_META_CSUM_ENABLE
static uint32_t ext4_dir_dx_checksum(struct ext4_inode_ref *inode_ref, void *de,
                     int count_offset, int count,
                     struct ext4_dir_idx_tail *t)
{
    uint32_t orig_cum, csum = 0;
    struct ext4_sblock *sb = &inode_ref->fs->sb;
    int sz;

    /* Compute the checksum only if the filesystem supports it */
    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
        uint32_t ino_index = to_le32(inode_ref->index);
        uint32_t ino_gen;
        ino_gen = to_le32(ext4_inode_get_generation(inode_ref->inode));

        sz = count_offset + (count * sizeof(struct ext4_dir_idx_tail));
        orig_cum = t->checksum;
        t->checksum = 0;
        /* First calculate crc32 checksum against fs uuid */
        csum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid, sizeof(sb->uuid));
        /* Then calculate crc32 checksum against inode number
         * and inode generation */
        csum = ext4_crc32c(csum, &ino_index, sizeof(ino_index));
        csum = ext4_crc32c(csum, &ino_gen, sizeof(ino_gen));
        /* After that calculate crc32 checksum against all the dx_entry */
        csum = ext4_crc32c(csum, de, sz);
        /* Finally calculate crc32 checksum for dx_tail */
        csum = ext4_crc32c(csum, t, sizeof(struct ext4_dir_idx_tail));
        t->checksum = orig_cum;
    }
    return csum;
}

static struct ext4_dir_idx_climit *
ext4_dir_dx_get_climit(struct ext4_inode_ref *inode_ref,
               struct ext4_dir_en *dirent, int *offset)
{
    struct ext4_dir_en *dp;
    struct ext4_dir_idx_root *root;
    struct ext4_sblock *sb = &inode_ref->fs->sb;
    uint32_t block_size = ext4_sb_get_block_size(sb);
    uint16_t entry_len = ext4_dir_en_get_entry_len(dirent);
    int count_offset;


    if (entry_len == 12) {
        root = (struct ext4_dir_idx_root *)dirent;
        dp = (struct ext4_dir_en *)&root->dots[1];
        if (ext4_dir_en_get_entry_len(dp) != (block_size - 12))
            return NULL;
        if (root->info.reserved_zero)
            return NULL;
        if (root->info.info_length != sizeof(struct ext4_dir_idx_rinfo))
            return NULL;
        count_offset = 32;
    } else if (entry_len == block_size) {
        count_offset = 8;
    } else {
        return NULL;
    }

    if (offset)
        *offset = count_offset;
    return (struct ext4_dir_idx_climit *)(((char *)dirent) + count_offset);
}

/*
 * BIG FAT NOTES:
 *       Currently we do not verify the checksum of HTree node.
 */
static bool ext4_dir_dx_csum_verify(struct ext4_inode_ref *inode_ref,
                    struct ext4_dir_en *de)
{
    struct ext4_sblock *sb = &inode_ref->fs->sb;
    uint32_t block_size = ext4_sb_get_block_size(sb);
    int coff, limit, cnt;

    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
        struct ext4_dir_idx_climit *climit;
        climit = ext4_dir_dx_get_climit(inode_ref, de, &coff);
        if (!climit) {
            /* Directory seems corrupted. */
            return true;
        }
        struct ext4_dir_idx_tail *t;
        limit = ext4_dir_dx_climit_get_limit(climit);
        cnt = ext4_dir_dx_climit_get_count(climit);
        if (coff + (limit * sizeof(struct ext4_dir_idx_entry)) >
            (block_size - sizeof(struct ext4_dir_idx_tail))) {
            /* There is no space to hold the checksum */
            return true;
        }
        t = (void *)(((struct ext4_dir_idx_entry *)climit) + limit);

        uint32_t c;
        c = to_le32(ext4_dir_dx_checksum(inode_ref, de, coff, cnt, t));
        if (t->checksum != c)
            return false;
    }
    return true;
}


static void ext4_dir_set_dx_csum(struct ext4_inode_ref *inode_ref,
                 struct ext4_dir_en *dirent)
{
    int coff, limit, count;
    struct ext4_sblock *sb = &inode_ref->fs->sb;
    uint32_t block_size = ext4_sb_get_block_size(sb);

    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
        struct ext4_dir_idx_climit *climit;
        climit = ext4_dir_dx_get_climit(inode_ref, dirent, &coff);
        if (!climit) {
            /* Directory seems corrupted. */
            return;
        }
        struct ext4_dir_idx_tail *t;
        limit = ext4_dir_dx_climit_get_limit(climit);
        count = ext4_dir_dx_climit_get_count(climit);
        if (coff + (limit * sizeof(struct ext4_dir_idx_entry)) >
           (block_size - sizeof(struct ext4_dir_idx_tail))) {
            /* There is no space to hold the checksum */
            return;
        }

        t = (void *)(((struct ext4_dir_idx_entry *)climit) + limit);
        t->checksum = to_le32(ext4_dir_dx_checksum(inode_ref, dirent,
                    coff, count, t));
    }
}
#else
#define ext4_dir_dx_csum_verify(...) true
#define ext4_dir_set_dx_csum(...)
#endif

/****************************************************************************/

int ext4_dir_dx_init(struct ext4_inode_ref *dir, struct ext4_inode_ref *parent)
{
    /* Load block 0, where will be index root located */
    ext4_fsblk_t fblock;
    uint32_t iblock = 0;
    bool need_append =
        (ext4_inode_get_size(&dir->fs->sb, dir->inode)
            < EXT4_DIR_DX_INIT_BCNT)
        ? true : false;
    struct ext4_sblock *sb = &dir->fs->sb;
    uint32_t block_size = ext4_sb_get_block_size(&dir->fs->sb);
    struct ext4_block block;

    int rc;

    if (!need_append)
        rc = ext4_fs_init_inode_dblk_idx(dir, iblock, &fblock);
    else
        rc = ext4_fs_append_inode_dblk(dir, &fblock, &iblock);

    if (rc != EOK)
        return rc;

    rc = ext4_trans_block_get_noread(dir->fs->bdev, &block, fblock);
    if (rc != EOK)
        return rc;

    /* Initialize pointers to data structures */
    struct ext4_dir_idx_root *root = (void *)block.data;
    struct ext4_dir_idx_rinfo *info = &(root->info);

    memset(root, 0, sizeof(struct ext4_dir_idx_root));
    struct ext4_dir_en *de;

    /* Initialize dot entries */
    de = (struct ext4_dir_en *)root->dots;
    ext4_dir_write_entry(sb, de, 12, dir, ".", strlen("."));

    de = (struct ext4_dir_en *)(root->dots + 1);
    uint16_t elen = block_size - 12;
    ext4_dir_write_entry(sb, de, elen, parent, "..", strlen(".."));

    /* Initialize root info structure */
    uint8_t hash_version = ext4_get8(&dir->fs->sb, default_hash_version);

    ext4_dir_dx_rinfo_set_hash_version(info, hash_version);
    ext4_dir_dx_rinfo_set_indirect_levels(info, 0);
    ext4_dir_dx_root_info_set_info_length(info, 8);

    /* Set limit and current number of entries */
    struct ext4_dir_idx_climit *climit;
    climit = (struct ext4_dir_idx_climit *)&root->en;

    ext4_dir_dx_climit_set_count(climit, 1);

    uint32_t entry_space;
    entry_space = block_size - 2 * sizeof(struct ext4_dir_idx_dot_en) -
            sizeof(struct ext4_dir_idx_rinfo);

    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
        entry_space -= sizeof(struct ext4_dir_idx_tail);

    uint16_t root_limit = entry_space / sizeof(struct ext4_dir_idx_entry);
    ext4_dir_dx_climit_set_limit(climit, root_limit);

    /* Append new block, where will be new entries inserted in the future */
    iblock++;
    if (!need_append)
        rc = ext4_fs_init_inode_dblk_idx(dir, iblock, &fblock);
    else
        rc = ext4_fs_append_inode_dblk(dir, &fblock, &iblock);

    if (rc != EOK) {
        ext4_block_set(dir->fs->bdev, &block);
        return rc;
    }

    struct ext4_block new_block;
    rc = ext4_trans_block_get_noread(dir->fs->bdev, &new_block, fblock);
    if (rc != EOK) {
        ext4_block_set(dir->fs->bdev, &block);
        return rc;
    }

    /* Fill the whole block with empty entry */
    struct ext4_dir_en *be = (void *)new_block.data;

    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
        uint16_t len = block_size - sizeof(struct ext4_dir_entry_tail);
        ext4_dir_en_set_entry_len(be, len);
        ext4_dir_en_set_name_len(sb, be, 0);
        ext4_dir_en_set_inode_type(sb, be, EXT4_DE_UNKNOWN);
        ext4_dir_init_entry_tail(EXT4_DIRENT_TAIL(be, block_size));
        ext4_dir_set_csum(dir, be);
    } else {
        ext4_dir_en_set_entry_len(be, block_size);
    }

    ext4_dir_en_set_inode(be, 0);

    ext4_trans_set_block_dirty(new_block.buf);
    rc = ext4_block_set(dir->fs->bdev, &new_block);
    if (rc != EOK) {
        ext4_block_set(dir->fs->bdev, &block);
        return rc;
    }

    /* Connect new block to the only entry in index */
    struct ext4_dir_idx_entry *entry = root->en;
    ext4_dir_dx_entry_set_block(entry, iblock);

    ext4_dir_set_dx_csum(dir, (struct ext4_dir_en *)block.data);
    ext4_trans_set_block_dirty(block.buf);

    return ext4_block_set(dir->fs->bdev, &block);
}

/**@brief Initialize hash info structure necessary for index operations.
 * @param hinfo      Pointer to hinfo to be initialized
 * @param root_block Root block (number 0) of index
 * @param sb         Pointer to superblock
 * @param name_len   Length of name to be computed hash value from
 * @param name       Name to be computed hash value from
 * @return Standard error code
 */
static int ext4_dir_hinfo_init(struct ext4_hash_info *hinfo,
                   struct ext4_block *root_block,
                   struct ext4_sblock *sb, size_t name_len,
                   const char *name)
{
    struct ext4_dir_idx_root *root;

    root = (struct ext4_dir_idx_root *)root_block->data;
    if ((root->info.hash_version != EXT2_HTREE_LEGACY) &&
        (root->info.hash_version != EXT2_HTREE_HALF_MD4) &&
        (root->info.hash_version != EXT2_HTREE_TEA))
        return EXT4_ERR_BAD_DX_DIR;

    /* Check unused flags */
    if (root->info.unused_flags != 0)
        return EXT4_ERR_BAD_DX_DIR;

    /* Check indirect levels */
    if (root->info.indirect_levels > 1)
        return EXT4_ERR_BAD_DX_DIR;

    /* Check if node limit is correct */
    uint32_t block_size = ext4_sb_get_block_size(sb);
    uint32_t entry_space = block_size;
    entry_space -= 2 * sizeof(struct ext4_dir_idx_dot_en);
    entry_space -= sizeof(struct ext4_dir_idx_rinfo);
    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
        entry_space -= sizeof(struct ext4_dir_idx_tail);
    entry_space = entry_space / sizeof(struct ext4_dir_idx_entry);

    struct ext4_dir_idx_climit *climit = (void *)&root->en;
    uint16_t limit = ext4_dir_dx_climit_get_limit(climit);
    if (limit != entry_space)
        return EXT4_ERR_BAD_DX_DIR;

    /* Check hash version and modify if necessary */
    hinfo->hash_version = ext4_dir_dx_rinfo_get_hash_version(&root->info);
    if ((hinfo->hash_version <= EXT2_HTREE_TEA) &&
        (ext4_sb_check_flag(sb, EXT4_SUPERBLOCK_FLAGS_UNSIGNED_HASH))) {
        /* Use unsigned hash */
        hinfo->hash_version += 3;
    }

    /* Load hash seed from superblock */
    hinfo->seed = ext4_get8(sb, hash_seed);

    /* Compute hash value of name */
    if (name)
        return ext4_dir_dx_hash_string(hinfo, name_len, name);

    return EOK;
}

/**@brief Walk through index tree and load leaf with corresponding hash value.
 * @param hinfo      Initialized hash info structure
 * @param inode_ref  Current i-node
 * @param root_block Root block (iblock 0), where is root node located
 * @param dx_block   Pointer to leaf node in dx_blocks array
 * @param dx_blocks  Array with the whole path from root to leaf
 * @return Standard error code
 */
static int ext4_dir_dx_get_leaf(struct ext4_hash_info *hinfo,
                struct ext4_inode_ref *inode_ref,
                struct ext4_block *root_block,
                struct ext4_dir_idx_block **dx_block,
                struct ext4_dir_idx_block *dx_blocks)
{
    struct ext4_dir_idx_root *root;
    struct ext4_dir_idx_entry *entries;
    struct ext4_dir_idx_entry *p;
    struct ext4_dir_idx_entry *q;
    struct ext4_dir_idx_entry *m;
    struct ext4_dir_idx_entry *at;
    ext4_fsblk_t fblk;
    uint32_t block_size;
    uint16_t limit;
    uint16_t entry_space;
    uint8_t ind_level;
    int r;

    struct ext4_dir_idx_block *tmp_dx_blk = dx_blocks;
    struct ext4_block *tmp_blk = root_block;
    struct ext4_sblock *sb = &inode_ref->fs->sb;

    block_size = ext4_sb_get_block_size(sb);
    root = (struct ext4_dir_idx_root *)root_block->data;
    entries = (struct ext4_dir_idx_entry *)&root->en;
    limit = ext4_dir_dx_climit_get_limit((void *)entries);
    ind_level = ext4_dir_dx_rinfo_get_indirect_levels(&root->info);

    /* Walk through the index tree */
    while (true) {
        uint16_t cnt = ext4_dir_dx_climit_get_count((void *)entries);
        if ((cnt == 0) || (cnt > limit))
            return EXT4_ERR_BAD_DX_DIR;

        /* Do binary search in every node */
        p = entries + 1;
        q = entries + cnt - 1;

        while (p <= q) {
            m = p + (q - p) / 2;
            if (ext4_dir_dx_entry_get_hash(m) > hinfo->hash)
                q = m - 1;
            else
                p = m + 1;
        }

        at = p - 1;

        /* Write results */
        memcpy(&tmp_dx_blk->b, tmp_blk, sizeof(struct ext4_block));
        tmp_dx_blk->entries = entries;
        tmp_dx_blk->position = at;

        /* Is algorithm in the leaf? */
        if (ind_level == 0) {
            *dx_block = tmp_dx_blk;
            return EOK;
        }

        /* Goto child node */
        uint32_t n_blk = ext4_dir_dx_entry_get_block(at);

        ind_level--;

        r = ext4_fs_get_inode_dblk_idx(inode_ref, n_blk, &fblk, false);
        if (r != EOK)
            return r;

        r = ext4_trans_block_get(inode_ref->fs->bdev, tmp_blk, fblk);
        if (r != EOK)
            return r;

        entries = ((struct ext4_dir_idx_node *)tmp_blk->data)->entries;
        limit = ext4_dir_dx_climit_get_limit((void *)entries);

        entry_space = block_size - sizeof(struct ext4_fake_dir_entry);
        if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
            entry_space -= sizeof(struct ext4_dir_idx_tail);

        entry_space = entry_space / sizeof(struct ext4_dir_idx_entry);

        if (limit != entry_space) {
            ext4_block_set(inode_ref->fs->bdev, tmp_blk);
            return EXT4_ERR_BAD_DX_DIR;
        }

        if (!ext4_dir_dx_csum_verify(inode_ref, (void *)tmp_blk->data)) {
            ext4_dbg(DEBUG_DIR_IDX,
                    DBG_WARN "HTree checksum failed."
                    "Inode: %" PRIu32", "
                    "Block: %" PRIu32"\n",
                    inode_ref->index,
                    n_blk);
        }

        ++tmp_dx_blk;
    }

    /* Unreachable */
    return EOK;
}

/**@brief Check if the the next block would be checked during entry search.
 * @param inode_ref Directory i-node
 * @param hash      Hash value to check
 * @param dx_block  Current block
 * @param dx_blocks Array with path from root to leaf node
 * @return Standard Error code
 */
static int ext4_dir_dx_next_block(struct ext4_inode_ref *inode_ref,
                  uint32_t hash,
                  struct ext4_dir_idx_block *dx_block,
                  struct ext4_dir_idx_block *dx_blocks)
{
    int r;
    uint32_t num_handles = 0;
    ext4_fsblk_t blk_adr;
    struct ext4_dir_idx_block *p = dx_block;

    /* Try to find data block with next bunch of entries */
    while (true) {
        uint16_t cnt = ext4_dir_dx_climit_get_count((void *)p->entries);

        p->position++;
        if (p->position < p->entries + cnt)
            break;

        if (p == dx_blocks)
            return EOK;

        num_handles++;
        p--;
    }

    /* Check hash collision (if not occurred - no next block cannot be
     * used)*/
    uint32_t current_hash = ext4_dir_dx_entry_get_hash(p->position);
    if ((hash & 1) == 0) {
        if ((current_hash & ~1) != hash)
            return 0;
    }

    /* Fill new path */
    while (num_handles--) {
        uint32_t blk = ext4_dir_dx_entry_get_block(p->position);
        r = ext4_fs_get_inode_dblk_idx(inode_ref, blk, &blk_adr, false);
        if (r != EOK)
            return r;

        struct ext4_block b;
        r = ext4_trans_block_get(inode_ref->fs->bdev, &b, blk_adr);
        if (r != EOK)
            return r;

        if (!ext4_dir_dx_csum_verify(inode_ref, (void *)b.data)) {
            ext4_dbg(DEBUG_DIR_IDX,
                    DBG_WARN "HTree checksum failed."
                    "Inode: %" PRIu32", "
                    "Block: %" PRIu32"\n",
                    inode_ref->index,
                    blk);
        }

        p++;

        /* Don't forget to put old block (prevent memory leak) */
        r = ext4_block_set(inode_ref->fs->bdev, &p->b);
        if (r != EOK)
            return r;

        memcpy(&p->b, &b, sizeof(b));
        p->entries = ((struct ext4_dir_idx_node *)b.data)->entries;
        p->position = p->entries;
    }

    return ENOENT;
}

int ext4_dir_dx_find_entry(struct ext4_dir_search_result *result,
               struct ext4_inode_ref *inode_ref, size_t name_len,
               const char *name)
{
    /* Load direct block 0 (index root) */
    ext4_fsblk_t root_block_addr;
    int rc2;
    int rc;
    rc = ext4_fs_get_inode_dblk_idx(inode_ref,  0, &root_block_addr, false);
    if (rc != EOK)
        return rc;

    struct ext4_fs *fs = inode_ref->fs;

    struct ext4_block root_block;
    rc = ext4_trans_block_get(fs->bdev, &root_block, root_block_addr);
    if (rc != EOK)
        return rc;

    if (!ext4_dir_dx_csum_verify(inode_ref, (void *)root_block.data)) {
        ext4_dbg(DEBUG_DIR_IDX,
             DBG_WARN "HTree root checksum failed."
             "Inode: %" PRIu32", "
             "Block: %" PRIu32"\n",
             inode_ref->index,
             (uint32_t)0);
    }

    /* Initialize hash info (compute hash value) */
    struct ext4_hash_info hinfo;
    rc = ext4_dir_hinfo_init(&hinfo, &root_block, &fs->sb, name_len, name);
    if (rc != EOK) {
        ext4_block_set(fs->bdev, &root_block);
        return EXT4_ERR_BAD_DX_DIR;
    }

    /*
     * Hardcoded number 2 means maximum height of index tree,
     * specified in the Linux driver.
     */
    struct ext4_dir_idx_block dx_blocks[2];
    struct ext4_dir_idx_block *dx_block;
    struct ext4_dir_idx_block *tmp;

    rc = ext4_dir_dx_get_leaf(&hinfo, inode_ref, &root_block, &dx_block,
                  dx_blocks);
    if (rc != EOK) {
        ext4_block_set(fs->bdev, &root_block);
        return EXT4_ERR_BAD_DX_DIR;
    }

    do {
        /* Load leaf block */
        uint32_t leaf_blk_idx;
        ext4_fsblk_t leaf_block_addr;
        struct ext4_block b;

        leaf_blk_idx = ext4_dir_dx_entry_get_block(dx_block->position);
        rc = ext4_fs_get_inode_dblk_idx(inode_ref, leaf_blk_idx,
                        &leaf_block_addr, false);
        if (rc != EOK)
            goto cleanup;

        rc = ext4_trans_block_get(fs->bdev, &b, leaf_block_addr);
        if (rc != EOK)
            goto cleanup;

        if (!ext4_dir_csum_verify(inode_ref, (void *)b.data)) {
            ext4_dbg(DEBUG_DIR_IDX,
                 DBG_WARN "HTree leaf block checksum failed."
                 "Inode: %" PRIu32", "
                 "Block: %" PRIu32"\n",
                 inode_ref->index,
                 leaf_blk_idx);
        }

        /* Linear search inside block */
        struct ext4_dir_en *de;
        rc = ext4_dir_find_in_block(&b, &fs->sb, name_len, name, &de);

        /* Found => return it */
        if (rc == EOK) {
            result->block = b;
            result->dentry = de;
            goto cleanup;
        }

        /* Not found, leave untouched */
        rc2 = ext4_block_set(fs->bdev, &b);
        if (rc2 != EOK)
            goto cleanup;

        if (rc != ENOENT)
            goto cleanup;

        /* check if the next block could be checked */
        rc = ext4_dir_dx_next_block(inode_ref, hinfo.hash, dx_block,
                        &dx_blocks[0]);
        if (rc < 0)
            goto cleanup;
    } while (rc == ENOENT);

    /* Entry not found */
    rc = ENOENT;

cleanup:
    /* The whole path must be released (preventing memory leak) */
    tmp = dx_blocks;

    while (tmp <= dx_block) {
        rc2 = ext4_block_set(fs->bdev, &tmp->b);
        if (rc == EOK && rc2 != EOK)
            rc = rc2;
        ++tmp;
    }

    return rc;
}

/**@brief  Compare function used to pass in quicksort implementation.
 *         It can compare two entries by hash value.
 * @param arg1  First entry
 * @param arg2  Second entry
 *
 * @return Classic compare result
 *         (0: equal, -1: arg1 < arg2, 1: arg1 > arg2)
 */
static int ext4_dir_dx_entry_comparator(const void *arg1, const void *arg2)
{
    struct ext4_dx_sort_entry *entry1 = (void *)arg1;
    struct ext4_dx_sort_entry *entry2 = (void *)arg2;

    if (entry1->hash == entry2->hash)
        return 0;

    if (entry1->hash < entry2->hash)
        return -1;
    else
        return 1;
}

/**@brief  Insert new index entry to block.
 *         Note that space for new entry must be checked by caller.
 * @param inode_ref   Directory i-node
 * @param index_block Block where to insert new entry
 * @param hash        Hash value covered by child node
 * @param iblock      Logical number of child block
 *
 */
static void
ext4_dir_dx_insert_entry(struct ext4_inode_ref *inode_ref __ext4_unused,
             struct ext4_dir_idx_block *index_block,
             uint32_t hash, uint32_t iblock)
{
    struct ext4_dir_idx_entry *old_index_entry = index_block->position;
    struct ext4_dir_idx_entry *new_index_entry = old_index_entry + 1;
    struct ext4_dir_idx_climit *climit = (void *)index_block->entries;
    struct ext4_dir_idx_entry *start_index = index_block->entries;
    uint32_t count = ext4_dir_dx_climit_get_count(climit);

    size_t bytes;
    bytes = (uint8_t *)(start_index + count) - (uint8_t *)(new_index_entry);

    memmove(new_index_entry + 1, new_index_entry, bytes);

    ext4_dir_dx_entry_set_block(new_index_entry, iblock);
    ext4_dir_dx_entry_set_hash(new_index_entry, hash);
    ext4_dir_dx_climit_set_count(climit, count + 1);
    ext4_dir_set_dx_csum(inode_ref, (void *)index_block->b.data);
    ext4_trans_set_block_dirty(index_block->b.buf);
}

/**@brief Split directory entries to two parts preventing node overflow.
 * @param inode_ref      Directory i-node
 * @param hinfo          Hash info
 * @param old_data_block Block with data to be split
 * @param index_block    Block where index entries are located
 * @param new_data_block Output value for newly allocated data block
 */
static int ext4_dir_dx_split_data(struct ext4_inode_ref *inode_ref,
                  struct ext4_hash_info *hinfo,
                  struct ext4_block *old_data_block,
                  struct ext4_dir_idx_block *index_block,
                  struct ext4_block *new_data_block)
{
    int rc = EOK;
    struct ext4_sblock *sb = &inode_ref->fs->sb;
    uint32_t block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);

    /* Allocate buffer for directory entries */
    uint8_t *entry_buffer = ext4_malloc(block_size);
    if (entry_buffer == NULL)
        return ENOMEM;

    /* dot entry has the smallest size available */
    uint32_t max_ecnt = block_size / sizeof(struct ext4_dir_idx_dot_en);

    /* Allocate sort entry */
    struct ext4_dx_sort_entry *sort;

    sort = ext4_malloc(max_ecnt * sizeof(struct ext4_dx_sort_entry));
    if (sort == NULL) {
        ext4_free(entry_buffer);
        return ENOMEM;
    }

    uint32_t idx = 0;
    uint32_t real_size = 0;

    /* Initialize hinfo */
    struct ext4_hash_info hinfo_tmp;
    memcpy(&hinfo_tmp, hinfo, sizeof(struct ext4_hash_info));

    /* Load all valid entries to the buffer */
    struct ext4_dir_en *de = (void *)old_data_block->data;
    uint8_t *entry_buffer_ptr = entry_buffer;
    while ((void *)de < (void *)(old_data_block->data + block_size)) {
        /* Read only valid entries */
        if (ext4_dir_en_get_inode(de) && de->name_len) {
            uint16_t len = ext4_dir_en_get_name_len(sb, de);
            rc = ext4_dir_dx_hash_string(&hinfo_tmp, len,
                             (char *)de->name);
            if (rc != EOK) {
                ext4_free(sort);
                ext4_free(entry_buffer);
                return rc;
            }

            uint32_t rec_len = 8 + len;
            if ((rec_len % 4) != 0)
                rec_len += 4 - (rec_len % 4);

            memcpy(entry_buffer_ptr, de, rec_len);

            sort[idx].dentry = entry_buffer_ptr;
            sort[idx].rec_len = rec_len;
            sort[idx].hash = hinfo_tmp.hash;

            entry_buffer_ptr += rec_len;
            real_size += rec_len;
            idx++;
        }

        size_t elen = ext4_dir_en_get_entry_len(de);
        de = (void *)((uint8_t *)de + elen);
    }

    qsort(sort, idx, sizeof(struct ext4_dx_sort_entry),
          ext4_dir_dx_entry_comparator);

    /* Allocate new block for store the second part of entries */
    ext4_fsblk_t new_fblock;
    uint32_t new_iblock;
    rc = ext4_fs_append_inode_dblk(inode_ref, &new_fblock, &new_iblock);
    if (rc != EOK) {
        ext4_free(sort);
        ext4_free(entry_buffer);
        return rc;
    }

    /* Load new block */
    struct ext4_block new_data_block_tmp;
    rc = ext4_trans_block_get_noread(inode_ref->fs->bdev, &new_data_block_tmp,
                   new_fblock);
    if (rc != EOK) {
        ext4_free(sort);
        ext4_free(entry_buffer);
        return rc;
    }

    /*
     * Distribute entries to two blocks (by size)
     * - compute the half
     */
    uint32_t new_hash = 0;
    uint32_t current_size = 0;
    uint32_t mid = 0;
    uint32_t i;
    for (i = 0; i < idx; ++i) {
        if ((current_size + sort[i].rec_len) > (block_size / 2)) {
            new_hash = sort[i].hash;
            mid = i;
            break;
        }

        current_size += sort[i].rec_len;
    }

    /* Check hash collision */
    uint32_t continued = 0;
    if (new_hash == sort[mid - 1].hash)
        continued = 1;

    uint32_t off = 0;
    void *ptr;
    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
        block_size -= sizeof(struct ext4_dir_entry_tail);

    /* First part - to the old block */
    for (i = 0; i < mid; ++i) {
        ptr = old_data_block->data + off;
        memcpy(ptr, sort[i].dentry, sort[i].rec_len);

        struct ext4_dir_en *t = ptr;
        if (i < (mid - 1))
            ext4_dir_en_set_entry_len(t, sort[i].rec_len);
        else
            ext4_dir_en_set_entry_len(t, block_size - off);

        off += sort[i].rec_len;
    }

    /* Second part - to the new block */
    off = 0;
    for (i = mid; i < idx; ++i) {
        ptr = new_data_block_tmp.data + off;
        memcpy(ptr, sort[i].dentry, sort[i].rec_len);

        struct ext4_dir_en *t = ptr;
        if (i < (idx - 1))
            ext4_dir_en_set_entry_len(t, sort[i].rec_len);
        else
            ext4_dir_en_set_entry_len(t, block_size - off);

        off += sort[i].rec_len;
    }

    block_size = ext4_sb_get_block_size(&inode_ref->fs->sb);

    /* Do some steps to finish operation */
    sb = &inode_ref->fs->sb;
    if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
        struct ext4_dir_entry_tail *t;

        t = EXT4_DIRENT_TAIL(old_data_block->data, block_size);
        ext4_dir_init_entry_tail(t);
        t = EXT4_DIRENT_TAIL(new_data_block_tmp.data, block_size);
        ext4_dir_init_entry_tail(t);
    }
    ext4_dir_set_csum(inode_ref, (void *)old_data_block->data);
    ext4_dir_set_csum(inode_ref, (void *)new_data_block_tmp.data);
    ext4_trans_set_block_dirty(old_data_block->buf);
    ext4_trans_set_block_dirty(new_data_block_tmp.buf);

    ext4_free(sort);
    ext4_free(entry_buffer);

    ext4_dir_dx_insert_entry(inode_ref, index_block, new_hash + continued,
                new_iblock);

    *new_data_block = new_data_block_tmp;
    return EOK;
}

/**@brief  Split index node and maybe some parent nodes in the tree hierarchy.
 * @param ino_ref Directory i-node
 * @param dx_blks Array with path from root to leaf node
 * @param dxb  Leaf block to be split if needed
 * @return Error code
 */
static int
ext4_dir_dx_split_index(struct ext4_inode_ref *ino_ref,
            struct ext4_dir_idx_block *dx_blks,
            struct ext4_dir_idx_block *dxb,
            struct ext4_dir_idx_block **new_dx_block)
{
    struct ext4_sblock *sb = &ino_ref->fs->sb;
    struct ext4_dir_idx_entry *e;
    int r;

    uint32_t block_size = ext4_sb_get_block_size(&ino_ref->fs->sb);
    uint32_t entry_space = block_size - sizeof(struct ext4_fake_dir_entry);
    uint32_t node_limit =  entry_space / sizeof(struct ext4_dir_idx_entry);

    bool meta_csum = ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM);

    if (dxb == dx_blks)
        e = ((struct ext4_dir_idx_root *)dxb->b.data)->en;
    else
        e = ((struct ext4_dir_idx_node *)dxb->b.data)->entries;

    struct ext4_dir_idx_climit *climit = (struct ext4_dir_idx_climit *)e;

    uint16_t leaf_limit = ext4_dir_dx_climit_get_limit(climit);
    uint16_t leaf_count = ext4_dir_dx_climit_get_count(climit);

    /* Check if is necessary to split index block */
    if (leaf_limit == leaf_count) {
        struct ext4_dir_idx_entry *ren;
        ptrdiff_t levels = dxb - dx_blks;

        ren = ((struct ext4_dir_idx_root *)dx_blks[0].b.data)->en;
        struct ext4_dir_idx_climit *rclimit = (void *)ren;
        uint16_t root_limit = ext4_dir_dx_climit_get_limit(rclimit);
        uint16_t root_count = ext4_dir_dx_climit_get_count(rclimit);


        /* Linux limitation */
        if ((levels > 0) && (root_limit == root_count))
            return ENOSPC;

        /* Add new block to directory */
        ext4_fsblk_t new_fblk;
        uint32_t new_iblk;
        r = ext4_fs_append_inode_dblk(ino_ref, &new_fblk, &new_iblk);
        if (r != EOK)
            return r;

        /* load new block */
        struct ext4_block b;
        r = ext4_trans_block_get_noread(ino_ref->fs->bdev, &b, new_fblk);
        if (r != EOK)
            return r;

        struct ext4_dir_idx_node *new_node = (void *)b.data;
        struct ext4_dir_idx_entry *new_en = new_node->entries;

        memset(&new_node->fake, 0, sizeof(struct ext4_fake_dir_entry));
        new_node->fake.entry_length = block_size;

        /* Split leaf node */
        if (levels > 0) {
            uint32_t count_left = leaf_count / 2;
            uint32_t count_right = leaf_count - count_left;
            uint32_t hash_right;
            size_t sz;

            struct ext4_dir_idx_climit *left_climit;
            struct ext4_dir_idx_climit *right_climit;

            hash_right = ext4_dir_dx_entry_get_hash(e + count_left);
            /* Copy data to new node */
            sz = count_right * sizeof(struct ext4_dir_idx_entry);
            memcpy(new_en, e + count_left, sz);

            /* Initialize new node */
            left_climit = (struct ext4_dir_idx_climit *)e;
            right_climit = (struct ext4_dir_idx_climit *)new_en;

            ext4_dir_dx_climit_set_count(left_climit, count_left);
            ext4_dir_dx_climit_set_count(right_climit, count_right);

            if (meta_csum)
                entry_space -= sizeof(struct ext4_dir_idx_tail);

            ext4_dir_dx_climit_set_limit(right_climit, node_limit);

            /* Which index block is target for new entry */
            uint32_t position_index =
                (dxb->position - dxb->entries);
            if (position_index >= count_left) {
                ext4_dir_set_dx_csum(
                        ino_ref,
                        (struct ext4_dir_en *)
                        dxb->b.data);
                ext4_trans_set_block_dirty(dxb->b.buf);

                struct ext4_block block_tmp = dxb->b;

                dxb->b = b;

                dxb->position =
                    new_en + position_index - count_left;
                dxb->entries = new_en;

                b = block_tmp;
            }

            /* Finally insert new entry */
            ext4_dir_dx_insert_entry(ino_ref, dx_blks, hash_right,
                         new_iblk);
            ext4_dir_set_dx_csum(ino_ref, (void*)dx_blks[0].b.data);
            ext4_dir_set_dx_csum(ino_ref, (void*)dx_blks[1].b.data);
            ext4_trans_set_block_dirty(dx_blks[0].b.buf);
            ext4_trans_set_block_dirty(dx_blks[1].b.buf);

            ext4_dir_set_dx_csum(ino_ref, (void *)b.data);
            ext4_trans_set_block_dirty(b.buf);
            return ext4_block_set(ino_ref->fs->bdev, &b);
        } else {
            size_t sz;
            /* Copy data from root to child block */
            sz = leaf_count * sizeof(struct ext4_dir_idx_entry);
            memcpy(new_en, e, sz);

            struct ext4_dir_idx_climit *new_climit = (void*)new_en;
            if (meta_csum)
                entry_space -= sizeof(struct ext4_dir_idx_tail);

            ext4_dir_dx_climit_set_limit(new_climit, node_limit);

            /* Set values in root node */
            struct ext4_dir_idx_climit *new_root_climit = (void *)e;

            ext4_dir_dx_climit_set_count(new_root_climit, 1);
            ext4_dir_dx_entry_set_block(e, new_iblk);

            struct ext4_dir_idx_root *r = (void *)dx_blks[0].b.data;
            r->info.indirect_levels = 1;

            /* Add new entry to the path */
            dxb = dx_blks + 1;
            dxb->position = dx_blks->position - e + new_en;
            dxb->entries = new_en;
            dxb->b = b;
            *new_dx_block = dxb;

            ext4_dir_set_dx_csum(ino_ref, (void*)dx_blks[0].b.data);
            ext4_dir_set_dx_csum(ino_ref, (void*)dx_blks[1].b.data);
            ext4_trans_set_block_dirty(dx_blks[0].b.buf);
            ext4_trans_set_block_dirty(dx_blks[1].b.buf);
        }
    }

    return EOK;
}

int ext4_dir_dx_add_entry(struct ext4_inode_ref *parent,
              struct ext4_inode_ref *child, const char *name, uint32_t name_len)
{
    int rc2 = EOK;
    int r;
    /* Get direct block 0 (index root) */
    ext4_fsblk_t rblock_addr;
    r =  ext4_fs_get_inode_dblk_idx(parent, 0, &rblock_addr, false);
    if (r != EOK)
        return r;

    struct ext4_fs *fs = parent->fs;
    struct ext4_block root_blk;

    r = ext4_trans_block_get(fs->bdev, &root_blk, rblock_addr);
    if (r != EOK)
        return r;

    if (!ext4_dir_dx_csum_verify(parent, (void*)root_blk.data)) {
        ext4_dbg(DEBUG_DIR_IDX,
             DBG_WARN "HTree root checksum failed."
             "Inode: %" PRIu32", "
             "Block: %" PRIu32"\n",
             parent->index,
             (uint32_t)0);
    }

    /* Initialize hinfo structure (mainly compute hash) */
    struct ext4_hash_info hinfo;
    r = ext4_dir_hinfo_init(&hinfo, &root_blk, &fs->sb, name_len, name);
    if (r != EOK) {
        ext4_block_set(fs->bdev, &root_blk);
        return EXT4_ERR_BAD_DX_DIR;
    }

    /*
     * Hardcoded number 2 means maximum height of index
     * tree defined in Linux.
     */
    struct ext4_dir_idx_block dx_blks[2];
    struct ext4_dir_idx_block *dx_blk;
    struct ext4_dir_idx_block *dx_it;

    r = ext4_dir_dx_get_leaf(&hinfo, parent, &root_blk, &dx_blk, dx_blks);
    if (r != EOK) {
        r = EXT4_ERR_BAD_DX_DIR;
        goto release_index;
    }

    /* Try to insert to existing data block */
    uint32_t leaf_block_idx = ext4_dir_dx_entry_get_block(dx_blk->position);
    ext4_fsblk_t leaf_block_addr;
    r = ext4_fs_get_inode_dblk_idx(parent, leaf_block_idx,
                        &leaf_block_addr, false);
    if (r != EOK)
        goto release_index;

    /*
     * Check if there is needed to split index node
     * (and recursively also parent nodes)
     */
    r = ext4_dir_dx_split_index(parent, dx_blks, dx_blk, &dx_blk);
    if (r != EOK)
        goto release_target_index;

    struct ext4_block target_block;
    r = ext4_trans_block_get(fs->bdev, &target_block, leaf_block_addr);
    if (r != EOK)
        goto release_index;

    if (!ext4_dir_csum_verify(parent,(void *)target_block.data)) {
        ext4_dbg(DEBUG_DIR_IDX,
                DBG_WARN "HTree leaf block checksum failed."
                "Inode: %" PRIu32", "
                "Block: %" PRIu32"\n",
                parent->index,
                leaf_block_idx);
    }

    /* Check if insert operation passed */
    r = ext4_dir_try_insert_entry(&fs->sb, parent, &target_block, child,
                    name, name_len);
    if (r == EOK)
        goto release_target_index;

    /* Split entries to two blocks (includes sorting by hash value) */
    struct ext4_block new_block;
    r = ext4_dir_dx_split_data(parent, &hinfo, &target_block, dx_blk,
                    &new_block);
    if (r != EOK) {
        rc2 = r;
        goto release_target_index;
    }

    /* Where to save new entry */
    uint32_t blk_hash = ext4_dir_dx_entry_get_hash(dx_blk->position + 1);
    if (hinfo.hash >= blk_hash)
        r = ext4_dir_try_insert_entry(&fs->sb, parent, &new_block,
                        child, name, name_len);
    else
        r = ext4_dir_try_insert_entry(&fs->sb, parent, &target_block,
                        child, name, name_len);

    /* Cleanup */
    r = ext4_block_set(fs->bdev, &new_block);
    if (r != EOK)
        return r;

/* Cleanup operations */

release_target_index:
    rc2 = r;

    r = ext4_block_set(fs->bdev, &target_block);
    if (r != EOK)
        return r;

release_index:
    if (r != EOK)
        rc2 = r;

    dx_it = dx_blks;

    while (dx_it <= dx_blk) {
        r = ext4_block_set(fs->bdev, &dx_it->b);
        if (r != EOK)
            return r;

        dx_it++;
    }

    return rc2;
}

int ext4_dir_dx_reset_parent_inode(struct ext4_inode_ref *dir,
                                   uint32_t parent_inode)
{
    /* Load block 0, where will be index root located */
    ext4_fsblk_t fblock;
    int rc = ext4_fs_get_inode_dblk_idx(dir, 0, &fblock, false);
    if (rc != EOK)
        return rc;

    struct ext4_block block;
    rc = ext4_trans_block_get(dir->fs->bdev, &block, fblock);
    if (rc != EOK)
        return rc;

    if (!ext4_dir_dx_csum_verify(dir, (void *)block.data)) {
        ext4_dbg(DEBUG_DIR_IDX,
             DBG_WARN "HTree root checksum failed."
             "Inode: %" PRIu32", "
             "Block: %" PRIu32"\n",
             dir->index,
             (uint32_t)0);
    }

    /* Initialize pointers to data structures */
    struct ext4_dir_idx_root *root = (void *)block.data;

    /* Fill the inode field with a new parent ino. */
    ext4_dx_dot_en_set_inode(&root->dots[1], parent_inode);

    ext4_dir_set_dx_csum(dir, (void *)block.data);
    ext4_trans_set_block_dirty(block.buf);

    return ext4_block_set(dir->fs->bdev, &block);
}

/**
 * @}
 */
